item {
  name: "vehicle"
  id: 1
  display_name: "vehicle"
}
item {
  name: "pedestrian"
  id: 2
  display_name: "pedestrian"
}
item {
  name: "sign"
  id: 3
  display_name: "sign"
}
item {
  name: "cyclist"
  id: 4
  display_name: "cyclist"
}
